In recent years, Electrical Impedance Spectroscopy (EIS) has become an important tool in analytical chemistry. EIS is typically used for analyzing the condition of solid state devices, batteries, fuel cells and liquid chemical samples. For electrochemical analysis of liquid samples, EIS is typically performed by placing a capacitive electrode into the sample to be measured. The liquid becomes the dielectric in the capacitive electrode and the variation in impedance, as a function of frequency, reveals information about the electrochemical properties of the sample. This information typically pertains to a chemical, physical, or electrical property of the sample.
It is highly preferable when performing EIS analysis of a material sample that the impedance-based measurement varies monotonically with variations in the chemical, physical or electrical property of the sample that is being evaluated. It is also preferable that the impedance-based measurement reveals quantitative information about the property of the sample. Unfortunately conventional EIS analysis does not always produce these preferable characteristics. What are needed therefore are improved systems and processes for electrical impedance spectroscopy.